Engine valve-gear mechanism.



PATENTED JULY 31, 1906.

W. GUEST. ENGINE VALVE GEAR MECHANISM.

APPLICATION FILED JANA, 1906.

3 SHEETS-SHEET 1.

w/mwwm THE NORRIS PET-5R5 cm, WASHINGTON, El'c.

PATENTED JULY 31, 1906.

W. W. GUEST. ENGINE VALVE GEAR MECHANISM.

. APPLIOATION FILED JANA/1906. v

' a snnmshsnmw 2.

("Mame/1 No. 827,232. PATENTED JULY 31,1906.

w.' w. GUEST. ENGINE VALVE GEAR MECHANISM.

AP PLIOATION FILED JANA, 1906.

3 SHEETS-SHEET 3.

' uua mum specification; of Letters Patent.

"Patented July 31,1906.

z-ijkpplioationfiled January t, 1906. Serial man-.628.

117011, wok/W1,v it mayconcern: @Be: it: known1 that I, ILLIAM GUEsnia" citizen. of the United States, residing at St. Louis, 'State of Missouri, haveinvented. oertain'ne-w andusefulImprovements iii-Engine IZalveGrear Mechanismy of-which thefolloW-f ring is a. full clear and exact: description, reference being-had to; the accompanying draw-y ings, formingwa part :hereof, My-invention has relation to improvements iin enginevalve gearmechanism; andit con-f sists in the novel construction and arrangerment ofrparts'more fully set-forth in the speciifieation and -pointed-outiin the claims. 5

tion; Oil a1!- doubleractingsteam engin-e, shoW-. ingsmy inventionv applied; thereto. Fig. .2 L is 5. a; toprplan thereof. ,Fig." 3-=is ;a verticalv longi-i' -tudinal: section through the cylinder, :taken i on the 5 line; 3 '3 of 1: F--ig.-;2. iFig. A? is a verticalf transverse section taken; through; thesteam- .chestomthe line AA oi'iFig. '1. Fig.5 is a ver-' *tical:. transverse section through I the cylinden onethe line. 5. ,5:- otFig. 91. Figs. GiSxLwVGl't-iQELli 2 5 stransverse section of the drive-shaft on v the: (line-,6 6 of :Eig.y2 ilooking-iinmthe direction-g off @the :plain arrow :therein .and showing rthe shaft-governor. ineinside elevation. 'Eig. 7,is; ;--.an--elevationaldetail of: one-oithe valves; andf 0 not the: terminal bell-crank secured to, the outerg' -:-end= ofv the valve-spindle. Fig. -8 is; a; transaverse section of the valve, taken-1on1 the. linej :8 8 ofg-iFi 7, 'FigQQ-is'Ean-enIar edverticalj sections through; the fdashpot,:taien on the; 3 5 -line'9i 9 ofF-ig. 5. iFig. 10:is';asection onthei 1- line 6.6. of. F ig;.-'2.ilo.oking" in the direction of: thei i featheredarroWrin.saidr figure. Fig. lLisa; "hvertical section on =the line 1 1 1 1; of "Fig. :10 ,g theshaft being in-elevation, showing the char-1 e tacter. of the cam formations :by ZWlllGlfl thel ivalves (both-divesteam and exhaust) :are;op;, erated. -F-ig. 12 isna vertical section on line; 51:21 1 2: of Fig. 1 1 showing; the specific cam for-] rnationsaby -which the exhaust-valvesare op erated .and. Figs. 13-and14 are diagrammatic -.:views:.showingv the positions of. the.-valve-ac-' 'Atuatingcam'under tWo different velocitiesof ithe; drive-shaft.

ETheobj ectof the present inventionis to ,pro- 5 0 Wide -23. valveear mechanism t in which a the movement of-t evalve in .one directionthat sis ii to sa'yythe cl0sing-inovement vvill :be'efected bythe'direct pressure Of-rSllBfiJIlf inathe asteamechest aand whilezthe-.chiefg importano l of the invention: resides; the suddenna'nd effective closing of the inlet. or steam valvetlie mechanism is vso designed ,that .it-will: effect *the; closing of the exhaust-valveas .W'elli The invention is conveniently adapted. and serviceableifor high-speed enginestwherefihe high VBlOOltY'Of the moving. parts requires an instantaneous .closing of ;the valve v(at (the ;point of cut-ofl.

A; further: object of; the invention. isitogpreserve the initia1.;pressure on the piston up to the i-momentof the cut-off,.thereby-efiecting Eperfect expansion and eliminating wiredraw ring, so! obj ectionablewith. the; majority ofenr5 ;In-the.draWing s, Figure :1 is a side --elevagines. Under such circumstancesthe Workof expansion will be represented bya trrilyadia- .batic curve sharply definedifrom? the steamline, as will be hereinafter more-1: fully appar- -ent.

A further." object is tonaccoinplishtheseatingeof the .valve with, a minimum? amount. of irnpact,- one which is unseatejd oropenedwvit'h .a minimurn expenditure of .power,' one gain .Whichundue-strain is: removed fromthe parts in: cooperative connection :vvitlnthe',v,alve, one applicable .to any motor-fiuid engine, 1: be it steam, ,air, -gas, I or other fluid, one whijch is sensitive 'i Ild directly and instantly r responsive to the variable 'velocities ,of ithedrive- .shaft and one possessing further and other -;advantages1-better apparent from @a detailed iiescription. of the invention, which; isqas folows:

Referring; to the, drawings, F represents-a suitable engine-frame, S the -driveeshaft, mounted therein, and.W,-W fly-Wheels amount- .ed at opposite ends otthe-shaft.

' (ll-represents the cylinder proper, the-. same :bein confinedWithimasectional ,ou ter cas- L'ingbetween whosentopand bottomiand endwalls res ectively, and the; corresponding Walls of t e cylinder; are 'afQIIIlGd cham- :bers A A serving,y-respectively .as live/and .exhaust steam chests. .The inletrpipeiis-rep- -:resented by -P,-and the exhaust by The frame F is suitablyhollowed. out to-accommodate "the double crank-arm :B, from hich leads the connecting-rodiR the oppositeend i of the connecting-rod being i. coupled to s; the 'gEStOIly-I'Od G,in turn connected to llhQg-PlStQll The partsdescribed: are-WelL-k-noWn-and I understood and require no special description, their operation being clear. Q

Disposed.- at :each. end of j the .chests 1 t \A from the cylinder.

from the specific construction of the valveand on opposite sides of the division-walls separating the chests, Fig. 3, are (preferably) rotary cylindrical steam and exhaust valves V V, respectively, of substantially similar construction except that the live-steam valve has series of three ports discharging into as many passages p p p, leading into the cylinder, whereas the exhaust-valve has series of two larger ports communicating with the corresponding passages 12 19, leading The valveports result body to be nowdescribed, special reference being had to Figs. 7 and 8, which represent the steam=valve-. The valve is composed of terminal circular heads'l 1, through which passes centrally the valve-spindle 2, the latter being provided with oblong blocks or keys 3, which enter corresponding openings formed in the heads, and since the keys are incapable of rotation within the heads it follows that when rotation or a rocking motion .is imparted to the spindle 2 a corresponding 'rotation or rocking motion is imparted to the heads. intermediate portion 4, forming a section of 2 .the peripheral wall of a cylinder, of which the The heads are connected with an heads 1 1 constitute the ends. This periph- "eral cylinder fportion 4 is provided with ports 0 in series 0 two, the longitudinal edge of f'saidiportion 4 forming a third port 0 with the outer bounding-wall of the adjacent passage 1 p, asfully shown on Fig. 3.

The outer end of'the spindle 2 is extended a suitable distance beyond the side vertical wall of the casing C and carries a bell-crank lever 5, the

forked end of one arm of which engages a laterally-projecting stud or pin 6 on the stem 7 of the dash-pot plunger 8, operating in the cylindrical cavity 9 of a basal extension 10 of e casing O The cushioning of the plunger is accomplished by the compression of the air confined between the plunger and a disk or block 11,which can be adjusted to secure any degree of compression by the screw 12, mounted on the gland or stuffing-box 13.

"The upper end of the stem 7 terminates in a piston 14, whose inner face is at all times exposed to the full pressure of the live steam in the overhanging extension A of the steamchest A, the tendency of the steam being to force the piston 14 and the plunger 8 downward. In such downward movement the bell-cranks and dash-pots are identical, the description for one suiiices for all, and the same reference-numbers are accordingly used for all of them, except that the exhaust steam bell crank's are identified by 5. As to the valves, the only difference between them is that the exhaust-valve controls two passages p 1) instead of three and the fur= ther difference that the terminal disks or ends 1 1 of the exhaust-valve have an additional peripheral connecting-section 4, Fig. 3, to afford an additional bearing a ainst the pressure of steam to which the valve is subjected by the live steam in drivin the piston H.

From the fore oing it will be seen that the closing of the va ve V V is accomplished by the direct action of the live steam through the movement of the dashot piston, which is at all times exposed to t e direct and full pressure of the steam in the steam-chest. The opening of the valves, on the other hand, is accomplished by a system of cams mounted on the drive-shaft, which cams actuate aseries of plungers in turn connected by means of links to the second arm of each of the bellcranks 5. These valve-opening devices may be described as follows: Leading forward toward the drive-shaft from each second arm of the bell-crank is a link or connecting rod 15, identified with the live-steam valves V and 15, identified with the exhaust-valves V. The forward ends of the links 15 are coupled to the upper ends of the oscillating levers 16, and the corresponding ends of the links 15 are coupled to the upper ends of corresponding levers 16, mounted on a spindle or shaft 17, projecting from the main frame F and in turn supported at its outer end by a bracket 18. In order that the several links 15 15 may all be disposed in parallel vertical planes side by side, the ends of the arms of the bellcranks to which the connection is made are necessarily provided with elongated pins or studs 19 19, as fully shown in Fi 1, to which pins the links 15 15 are pivotr lly coupled. The ends of the lower arms of the oscillating levers 16 16 are in turn coupled to a series of reciprocating plungers 2O 20, said plungers loosely operating througho )enings formed in a supporting arm or brac wt 21, projecting laterally from the engine-frame, the free ends of the plungers terminating in reduced pawls 22 22, respectively, a shoulder 23 being formed on each side of each pawl with the body of the plunger, as clearly shown in Figs. 1 and 10. The pawls 22 22 of the respective plungers 20 20 ride over suitable cam formations on the shaft, said cams forcing the plungers in one direction, whereby the levers 16 16are oscillated in proper direction to exert a pull on thelinks 15 15, and thus rock the bell-cranks 5 5 in proper direction to open the valves V V, the steam, through the medium of the dash-pot plungers, on the other hand, seating or rocking parts beinlg1 the valves to a closed position the instant-that appear from the construction of the cams, 'which I will now'describe.

Mounted loosely on the shaft S adjacent to the ,fly-wheel W and rotatable freely about said shaft is a triangular member or late 24, having a hub portion 25, With which ub ortion is integrally formed a circular dis or rider 26, the center of rotation of these on the axis of the shaft S. Secured to t e shaft next to the disk 26 is an eccentric 27, whose center is disposed on one side of the axis of the shaft Disposed.

loosely on the shaft next the eccentric .is a second disk or rider 26, Fig. 11-. Secured to the shaft next the disk 26 is a second eccentric 27, whose centeris on the opposite side of the axis of the shaftthat is, one hundred U and eighty degrees from the center of the eccentric 27. Loosely mounted on the shaft next the eccentric 27 is a third disk or rider 26. The disk 26 is i ovided with laterallyprojecting pins 28, which pass throughthe disks 26 26", the pins coupling'the several disks together and permitting them to rewhich the cams rotate.

, volveas a unit with the late 24 when rotation is imparted to'the atter, be such rotationv in unison with the shaft orindependent thereof. ,Mounted looselyover the peri hcries of the eccentrics '27 27 androtata le freely about the centers of the respective eccentrics are cams 29 29,'respectively, the

cams being rovided with elongated openings 30 for the 1 ee passage of the pins 28 therethrough, the openings 30 being elongated sufficiently in a radial direction to allow for the variations in the distances of the pins 28 from the centers of the eccentrics about For-the present it willbe suflicient to state that as the plate 24 rotates about the shaft the:several riders 26 '26 26 will rotate in unison'withit, the pins 28 in turn rotating the-cams about the eccentrics, and it may be stated in passing that the cams 29 29 actuate the pawls 22 of the plungers 2O 20, the latter in'turn controlling the links 15 15, which lead from the live-steam valves V, the valves being rocked to their open position by the cams, as presently to a pear. Keyed to-the shaft S adjacent to t e rider 26 and spaced suitable distances apart are disks or riders 31 31 31 and between .them are frictionally or otherwise held the. earns 32 32, the eccentric formations of which are substantially one hundred and eighty degrees apart to conform with a similar disposition between-thecams 29 29 The cams 32 32 actuate the pawls 22 of the plungers 20 the. latter in turn controlling the links 15, which lead from the exhaust valves V. The plungers 2O 20rest with their shoulders 23 etween their corresponding pairs of riders 26 course is such as to keep the valve V 22 thereof projecting between the .riders to engage with the eccentric formatlons of the steam behind the piston, and one exhaustvalve V must be open to release the exhauststeam from in front of the piston. This condition is already shown in Figs. 1 and 3, where the piston is beginning a stroke toward the right, and it is for this reason that the cams 29 29 32 32 are set one hundred and eighty degrees apart, since it is at each half-revolution of the shaft that the respective valves controlling the live and exhaust steam must be shifted. The cams are all of substantially the same contour, the eccentric formation of each terminating in a. nose-n, (n forthe exhaust-valves,) the noses of the respective pairs of cams being one hundred and eighty degrees apart, the noses-0f cams 29 32 and 29 32 being identified with the s ecific pairs of cams which control correspon valves V V.

In Figs. 1, 2, 3 the eccentric-formations of the cams 29 32 have, in fact, forced their respective pair of plungers 2O 20 rearwardly, these in turn having oscillated their particular levers 16 16 in proper direction to exert their ng pairs of pull on the links 15 15 and rock the valves V V, as shown in Fig. 3,'to their open position. The formation of the live-steam cam is such as to keep the valve V open for substantially two-thirds of the piston-stroke or .while the cam is'passing an arc of one hundred and twenty degrees revolution. When that is reached, the pawl of the plunger passes off the nose n, forming the terminal of the cam formation, the release of the plunger from the cam formation permitting the steampressure to suddenly depress the dash-pot plunger, whose stem 7 is coupled to the bellcrank 5, and thus instantly rock the valve to a closed position. For the remainder of the piston-stroke the steam acts by expansion. The formation of the exhaust-steam cam of 0 en during a full stroke of the piston in order to enable the steam to exhaust till the end of the stroke is reached. When that happens,

the next set of cams 29 32 are brought into requisition, whereupon the right-hand valve V and left-hand exhaust-valve V are opened to start the piston in the opposite direction, it being understood that at the end of the stroke just completed the right-hand exhaust-valve V was closed in the manner described for the valve Vthat is to say, by means of steam actuating the dash-pot plunger identified with said valve. The valve V, which,.as stated, comes to a closed position at the end of a two-thirds stroke of the piston,

remains closed not only for the last third of the pistons stroke, but for the full return stroke of the pistonthat is to say, for a revolution of the shaft through two hundred and forty degreeswhile the exhaust-valve remains closed for only one hundred and eighty degrees of the shafts revolution. This is obvious, of course, since the live steam works by expansion for the last third of the pistons stroke, which means sixty-degrees revolution, and it must remain closed for the full return of the pistons stroke, which corresponds to one hundred and eighty degrees revolution or a total of two hundred and forty degrees. The exhaust-valve, on the other hand, 0 ens and closes at the end of each stroke 0 the pistonthat is, with each one hundred and eighty degrees revolution.

The explanation as given above for the action of the" cams is on the assumption that the several cams revolve in unison with the shaft S. So far as the exhaust-valve cams 32 32 are concerned that is a fact j but so far as the live-steam earns 29 29 are concerned that is not always true, since their speed of rotation is controlled by the shaft-governor to which the plate 24 is directly coupled, it being remembered that the said plate is capable of rotation independent of theshaft, being mounted loosely thereon. If the shaft revolves too rapidly, the governor mechanism will impart to the plate/24 a slight rotation about and in advance of the angular velocity of the shaft, the angle through which the plate is thus moved determining the angle through which the riders 26 26 26 shall be rotated about the shaft, and hence determining the angle through which the earns 29 29 (through the medium of the pins 28) shall be rotated about the eccentrics 27 27. This independent movement thus imparted to the cams about their eccentrics directly controls the extent of the cam formation which is available for actuating or pushing the plungers outwardly to rock the steam-valves to their open position.

Before attempting a description of the shaft-governor by which independent angular movements are imparted to the plate 24 about the shaft S according to the speed of rotation of said shaft, I will for the time being assume such movement for purposes of explaining the effect on the available'length or extent of the eccentric portion of the cam (29 29) by which the plunger 20 is actuated. This explanation'will be best understood by a reference to the diagrammatic views shown in Figs. 13, 14, which illustrate two positions of the cam with respect to the eccentric mounted on the shaft. In these views the point I) represents the center of the shaft S, the point 0 the center of the eccentric 27, and 1" represents a circle concentric with the shaft and with the riders on the shaft. The cam 29 comprises an outer eccentric section described from the center 0 with a radius equal to b'r, and extending for substantially one hundred and twenty degrees from the point e to the point h, at which latter point the arc eh merges with or is tangent to the circle 1". At the point e is formed the nose at of the cam, the depth of the nose extendin -from the point e to the circle 1". From the base of the nose is struck an arc of one hundred and twenty degrees extending to the point g with a radius equal br minus bc, and from c as a center. The balance of the cam from 'g to h may be of any curvature so longas it comes within the circle r.

Referring again to Fig. 13, if we consider for the moment that the parts S, 27, and 29 revolveas a unit about the center I) then the section e-h, being the only portion of the cam outside the circle 7, will be available for pushing against the pawl 22, and thus push outwardly the plungerwhich said pawl terminates. As this unit revolves the valve-will be open for a period of time corresponding to the cam-section eh, or one hundred and twenty degrees revolution of the shaft, when the pawl 22 drops down the nose n and. for two hundred and forty degrees travels along the cam, first to g and thence to h, but always inside the circle 1", so that for two hundred and forty degrees the valve will remain closed, (beingrocked to'said position by the action of the live steam on the piston of the dash-pot plunger, which is coupled to the valve through the bell-crank connection described,) being that there is no eccentric portion outside the circle 1" to displace the inner most position of the pawl 22. The one-hundred and twenty degrees shaft-revolution represents the maximum'length of time during which the valve V may remain open. Suppose now that the engine is running too fast. The following then results: It must beremembered that the cam 29 is rotatable freely about the eccentric 27, the cam rotating about the center 0 of the eccentric. Referring now to Fig. 14, it will be seen that the cam has gained on the eccentric and shaft, this gain resulting from the independent angular advance given the cam by the shaftgovernor as a result of a too great speed.

Now since the arc eh described from c as a center will always be tangent to the circle r at the point h it follows that with any independent angular advance'of' the cam over the eccentric the available length of the arc e-lt (or that portion which is-outside the circle 1') will be reduced or shortened, so that now the pawl 22 will be affected for such reduced length of the arc eh, (being about sixty degrees in Fig. 14,) the valve remaining open for a much less time and closed for a greater length of time, (three hundred degrees.) The angular advance under a very high speed may be so increased as to cut the available length of the arc e-h to only a few degrees, in which event the steam would be excluded from the cylinder until the engine had been materially reduced in speed;'but whatever may be the degree of angular advance of'the cam over theeccentric no portion of the cams cur' vature beyond the tangent pointh (which is For this reason the available cam-surface operating the pawls 22 is virtually one .hundred and eighty degrees.

Having described the manner by which the pawls '22 22 are displaced by the cams to push their respective plungers in the proper direction to impart the necessary rocking motion to the valves for opening the same, I will vnow describe the 'shaft governor, by which inde endent angular movement is imparted to t e plate 24, to which the cams are coupled. In the present case the governor consists of a series of sliding weights 33, mounted on radial arms 34 of the fly-wheel W, the Weights being forced inwardly by the hinged arms 35, carried on each face of the fly-Wheel by the parts 34, the arms being controlled by the contracting springs 36, mounted behind the lobes 37 cast with the arms. The inner faces of the weights are pivotally coupled to the corners of the plate 24 by curved links 38: By reference to Fig. 6 it is obvious that should the speed of the shaft (revolving as indicated by. the arrow) S materially increase the centrifugal force will drive the weights 33 radially outward, in which movement they will draw on the links 38, thereby giving-the plate 24 an independent rotation or angular movement independent of and in advance of the shaft. This angular advance of the late 24 of, course imparts rotation to .the ri ers 26 26 26, and these in turn,

through the medium of the pins 28, will impart the necessary angular advance to the cams 29 29, thereby reducing the time during which the valves V V will remain in their open position. The device is therefore selfregulating.

Obviously'the eccentrics 27 27 are set one hundred and eighty degrees apart, since the cams 29 29 are brought into requisition with each alternate stroke. When a plunger is pushed in proper direction to rock a valve to an open positlon, the dash-pot plunger offers no resistance to the upward rocking motion of the bell-crank which actuates it except the resistance of its own weight, the steam-pressure bearing on the piston 14 thereof being for all essential purposes balanced by the air compressed between the plunger 8 and block 11. There is therefore no material strain on .the plungers and intermediate connections;

On the other hand, the-moment a pawl 22 22 passes the point e of the cam 29- 29, Figs- 13,

14, or the corresponding point on the cam 32 32, that instant the steam in the steam-chest forces the dash-pot plunger downward and W instantly closes the valve, the valve being rocked to such closed position by the downward movement of the stem 7 actuating the bell-crank coupled to the valve-spindle; but

though the closing of the valve 1s instanta-J neous, yet the same takes place without a ar, owing to the cushioning of the plunger 8 by the air compressed beneath it.

By reason of the instantaneous closing of the valve at the with my improvement may be run with a maximum degree of speed. The valves here point of cut-oif e an engine shown, though rock-valves, may be slidevalves without departing from the spirit of I.

my invention.

Having described my invention, what I claim isl 1. In an engine, a steam-valve, means coupled thereto for actuating thevalve in one direction, an eccentric on the engine-shaft, a cam rotatable about said eccentric, and intermediate connections between the camandvalve for=actuating the valve in the opposite direction, substantially as set forth.

2. In an engine having a cylinder and pis ton, a steam-valve therefor, a drive-shaft,

IOO

cam formations disposed on and rotatable about the shaft for actuating the valve in one direction, and means controlled by the'pressure of live steam for actuating the valve in the opposite direction, substantially as set, forth. p i

3. In an engine having a cylinder and pis- .ton,.a drive-shaft, eccentricson the shaft,

cams rotatable freely about. the eccentrics, means for imparting an angular advance to the cams independent of the angular velocity of the eccentrics and thereby varying the available effective cam formation about the eccentric, steam-valves for the cylinder, in-

termediate connections between the cams and valves for actuating the latter in one direction, and means controlled by the pressure of the live steam for actuating the valves, I

in the opposite direction, substantially as set forth.

4. In an engine, a drive-shaft, an eccentric on the shaft, a cam rotatable about the eccentric. and having a center of rotation concentric with the eccentric, and having a formation concentric with such center, one end of such formation being tangent to a circle concentric with the center of the shaft, the

opposite end of said formation terminating in a nose or depression, the remaining portions of the cam being disposed within the circle defining the base of said nose and concentric with the shaft, a valve for the engine, and intermediate connections between the valve and cam for actuating the valve in one direction upon engagement of said connections with the cam formation aforesaid, substantially as set forth.

5. In an engine, a drive-shaft, an eccentric on the shaft, a cam rotatable about the eccentric and having a center of rotation concentric with the eccentric, a formation on the cam concentric with such center but eccentric to the center of the shaft, one end of such formation being tangent to a circle concentrio with the shaft center, the opposite end of said formation terminating in a nose or depression, the remaining portions of the cam eing disposed within a circle interior to the base of the nose and concentric with the shaft center, a valve for the engine, intermediate connections between the valve and A cam for actuating the valve in one direction upon engagement of said connections with the cam formation aforesaid, and means controlled by the pressure of the steam for actu ating the valve in the opposite direction, substantially as set forth.

6. In an engine, a drive-shaft, a governor on the shaft, a system of cams rotatable about the shaft and coupled to the governor and adapted to have imparted thereto an angular movement independent of the rotation of the shaft, valves for the engine, intermediate connections interposed between the cams and valves for actuating the latter in one direction upon rotation of the shaft and earns, the intervals of actuation depending on the degree of angular movement imparted to the cams, and devices controlled by the steam-pressure for actuating the valves in the opposite direction upon their release from the influence of the cams, substantially as set forth.

7. In an engine, a drive-shaft, a shaft-governor, a member freely rotatable about the shaft and controlled by said governor, a pair of eccentrics spaced suitable distances apart formed on the shaft in proximity to said rotatable member, annular disks or riders freely rotatable about the shaft and disposed on opposite sides of the eccentrics, pins for coupling the riders together, the terminal rider of the series being secured to the rotatable member, cams rotatably mounted about the eccentrics and having slots for the passage of the pins aforesaid, a series of reciprocating plungers bearing on the riders and terminating in pawls adapted to be actuated by the cams, a series of steam and exhaust rockvalves for the engine, bell-cranks coupled to the valve-spindles and having each an arm coupled to a plunger, and steam-actuated dash-pot plungers having each a stem coupled to the second arm of the bell-crank, the parts operating substantially as, and for the purpose set forth.

8. In an engine, a steam-valve, a steam actuated dash-pot plunger coupled thereto for actuating the valve in one direction, a cam rotatable about the engine-shaft, and intermediate connections between the cam and valve for actuating the valve in the opposite direction, substantially as set forth.

9. In an engine, a steam-valve, a steamactuated dash-pot plunger coupled thereto for actuating the valve in one direction, an eccentric on the engine-shaft, a cam rotatable about said eccentric, and intermediate connections between the cam and valve for actuating the valve in the opposite direction, substantially as set forth.

In testimony whereof I affix my signature in presence of two Witnesses.

WILLIAM W. GUEST.

Witnesses:

EMIL STAREK, Jos. A; MroHEL. 

